Not sure if there is a toy to help you eat. Of course there are plenty you can use to stimulate her. Perhaps have her show you how she wants it. She can show you her tongue techniques on your penis while you watch.

If you were the first for each other, who is she comparing you to? Just a thought.

And actually, your tongue size, like penis length should not make much difference, after all the clitoris is easy to get to. I think a lot of guys get too focused on hitting the clit hard and fast, so maybe try a more gentle approach, licking her as gently as possible, and around the vulva and finally when she can stand it no longer, work the clitoris to set her off. Take your time with it, it's not a race.

I agree, the best thing is getting her input to find out what she likes/enjoys/wants. I know I experiment with my partner and listen/watch/feel for feedback on if something is enjoyed or not.

At the end of the day, every person is different and the only way to maximize their enjoyment is to ask them what they like and get feedback as you go. But if you are her only experience it might be you both need inspiration, the site OMGYES might be a great place to start for different ways women gain enjoyment through sexual stimulation w/ actual survey data to back up the different approaches, "hands on" practice, and tutorial videos. I joined the site to give my girlfriend inspiration for self exploration, since she was a virgin when we started dating and sometimes the best way to find out what you enjoy is through self exploration.